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<H1 class="no-header">curs_slk 3x 2023-09-16 ncurses 6.4 Library calls</H1>
<PRE>
<STRONG><A HREF="curs_slk.3x.html">curs_slk(3x)</A></STRONG>                     Library calls                    <STRONG><A HREF="curs_slk.3x.html">curs_slk(3x)</A></STRONG>




</PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
       <STRONG>slk_init</STRONG>,  <STRONG>slk_set</STRONG>,  <STRONG>slk_wset</STRONG>, <STRONG>slk_refresh</STRONG>, <STRONG>slk_noutrefresh</STRONG>, <STRONG>slk_label</STRONG>,
       <STRONG>slk_clear</STRONG>,    <STRONG>slk_restore</STRONG>,    <STRONG>slk_touch</STRONG>,    <STRONG>slk_attron</STRONG>,    <STRONG>slk_attrset</STRONG>,
       <STRONG>slk_attroff</STRONG>,   <STRONG>slk_attr_on</STRONG>,   <STRONG>slk_attr_set</STRONG>,   <STRONG>slk_attr_off</STRONG>,   <STRONG>slk_attr</STRONG>,
       <STRONG>slk_color</STRONG>, <STRONG>extended_slk_color</STRONG> - <EM>curses</EM> soft label key routines


</PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
       <STRONG>#include</STRONG> <STRONG>&lt;curses.h&gt;</STRONG>

       <STRONG>int</STRONG> <STRONG>slk_init(int</STRONG> <EM>fmt</EM><STRONG>);</STRONG>

       <STRONG>int</STRONG> <STRONG>slk_set(int</STRONG> <EM>labnum</EM><STRONG>,</STRONG> <STRONG>const</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG><EM>label</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>fmt</EM><STRONG>);</STRONG>
       <STRONG>int</STRONG> <STRONG>slk_wset(int</STRONG> <EM>labnum</EM><STRONG>,</STRONG> <STRONG>const</STRONG> <STRONG>wchar_t</STRONG> <STRONG>*</STRONG><EM>label</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>fmt</EM><STRONG>);</STRONG>

       <STRONG>char</STRONG> <STRONG>*slk_label(int</STRONG> <EM>labnum</EM><STRONG>);</STRONG>

       <STRONG>int</STRONG> <STRONG>slk_refresh(void);</STRONG>
       <STRONG>int</STRONG> <STRONG>slk_noutrefresh(void);</STRONG>
       <STRONG>int</STRONG> <STRONG>slk_clear(void);</STRONG>
       <STRONG>int</STRONG> <STRONG>slk_restore(void);</STRONG>
       <STRONG>int</STRONG> <STRONG>slk_touch(void);</STRONG>

       <STRONG>int</STRONG> <STRONG>slk_attron(const</STRONG> <STRONG>chtype</STRONG> <EM>attrs</EM><STRONG>);</STRONG>
       <STRONG>int</STRONG> <STRONG>slk_attroff(const</STRONG> <STRONG>chtype</STRONG> <EM>attrs</EM><STRONG>);</STRONG>
       <STRONG>int</STRONG> <STRONG>slk_attrset(const</STRONG> <STRONG>chtype</STRONG> <EM>attrs</EM><STRONG>);</STRONG>
       <STRONG>int</STRONG> <STRONG>slk_attr_on(attr_t</STRONG> <EM>attrs</EM><STRONG>,</STRONG> <STRONG>void*</STRONG> <EM>opts</EM><STRONG>);</STRONG>
       <STRONG>int</STRONG> <STRONG>slk_attr_off(const</STRONG> <STRONG>attr_t</STRONG> <EM>attrs</EM><STRONG>,</STRONG> <STRONG>void</STRONG> <STRONG>*</STRONG> <EM>opts</EM><STRONG>);</STRONG>
       <STRONG>int</STRONG> <STRONG>slk_attr_set(const</STRONG> <STRONG>attr_t</STRONG> <EM>attrs</EM><STRONG>,</STRONG> <STRONG>short</STRONG> <EM>pair</EM><STRONG>,</STRONG> <STRONG>void*</STRONG> <EM>opts</EM><STRONG>);</STRONG>
       /* extension */
       <STRONG>attr_t</STRONG> <STRONG>slk_attr(void);</STRONG>

       <STRONG>int</STRONG> <STRONG>slk_color(short</STRONG> <EM>pair</EM><STRONG>);</STRONG>
       /* extension */
       <STRONG>int</STRONG> <STRONG>extended_slk_color(int</STRONG> <EM>pair</EM><STRONG>);</STRONG>


</PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
       The slk* functions manipulate the set of soft function-key labels  that
       exist  on  many  terminals.   For those terminals that do not have soft
       labels, <STRONG>curses</STRONG> takes over the bottom line of <STRONG>stdscr</STRONG>, reducing the  size
       of  <STRONG>stdscr</STRONG> and the variable <STRONG>LINES</STRONG>.  <STRONG>curses</STRONG> standardizes on eight labels
       of up to eight characters each.   In  addition  to  this,  the  ncurses
       implementation  supports  a  mode where it simulates 12 labels of up to
       five characters each.  This is  useful  for  PC-like  enduser  devices.
       ncurses  simulates  this  mode  by  taking  over up to two lines at the
       bottom of the screen; it does not try to use any hardware  support  for
       this mode.


</PRE><H3><a name="h3-Initialization">Initialization</a></H3><PRE>
       The  <STRONG>slk_init</STRONG>  routine  must  be  called  before  <STRONG>initscr</STRONG> or <STRONG>newterm</STRONG> is
       called.  If <STRONG>initscr</STRONG> eventually uses a line from <STRONG>stdscr</STRONG> to  emulate  the
       soft  labels,  then  <EM>fmt</EM>  determines how the labels are arranged on the
       screen:

          <STRONG>0</STRONG>  indicates a 3-2-3 arrangement of the labels.

          <STRONG>1</STRONG>  indicates a 4-4 arrangement

          <STRONG>2</STRONG>  indicates the PC-like 4-4-4 mode.

          <STRONG>3</STRONG>  is again the PC-like 4-4-4 mode, but in addition an index line is
             generated, helping the user to identify the key numbers easily.


</PRE><H3><a name="h3-Labels">Labels</a></H3><PRE>
       The  <STRONG>slk_set</STRONG>  routine  (and the <STRONG>slk_wset</STRONG> routine for the wide-character
       library) has three parameters:

          <EM>labnum</EM>
               is the label number, from <STRONG>1</STRONG> to <STRONG>8</STRONG> (12 if <EM>fmt</EM> in <STRONG>slk_init</STRONG> is <STRONG>2</STRONG> or
               <STRONG>3</STRONG>);

          <EM>label</EM>
               is  be the string to put on the label, up to eight (five if <EM>fmt</EM>
               in <STRONG>slk_init</STRONG> is <STRONG>2</STRONG> or <STRONG>3</STRONG>) characters in length.  A null string  or
               a null pointer sets up a blank label.

          <EM>fmt</EM>  is  either  <STRONG>0</STRONG>,  <STRONG>1</STRONG>,  or <STRONG>2</STRONG>, indicating whether the label is to be
               left-justified,  centered,  or  right-justified,  respectively,
               within the label.

       The  <STRONG>slk_label</STRONG>  routine  returns  the  current  label  for label number
       <EM>labnum</EM>, with leading and trailing blanks stripped.


</PRE><H3><a name="h3-Screen-updates">Screen updates</a></H3><PRE>
       The <STRONG>slk_refresh</STRONG> and <STRONG>slk_noutrefresh</STRONG> routines correspond to the <STRONG>wrefresh</STRONG>
       and <STRONG>wnoutrefresh</STRONG> routines.

       The <STRONG>slk_clear</STRONG> routine clears the soft labels from the screen.

       The  <STRONG>slk_restore</STRONG> routine restores the soft labels to the screen after a
       <STRONG>slk_clear</STRONG> has been performed.

       The <STRONG>slk_touch</STRONG> routine forces all the soft labels to be output the  next
       time a <STRONG>slk_noutrefresh</STRONG> is performed.


</PRE><H3><a name="h3-Video-attributes">Video attributes</a></H3><PRE>
       The   <STRONG>slk_attron</STRONG>,   <STRONG>slk_attrset</STRONG>,   <STRONG>slk_attroff</STRONG>  and  <STRONG>slk_attr</STRONG>  routines
       correspond to <STRONG>attron</STRONG>,  <STRONG>attrset</STRONG>,  <STRONG>attroff</STRONG>  and  <STRONG>attr_get</STRONG>,  respectively.
       They  have  an  effect  only if soft labels are simulated on the bottom
       line of the screen.  The default highlight for soft keys is  A_STANDOUT
       (as in System V curses, which does not document this fact).


</PRE><H3><a name="h3-Colors">Colors</a></H3><PRE>
       The  <STRONG>slk_color</STRONG> routine corresponds to <STRONG>color_set</STRONG>.  It has an effect only
       if soft labels are simulated on the bottom line of the screen.

       Because <STRONG>slk_color</STRONG> accepts only <STRONG>short</STRONG> (signed  16-bit  integer)  values,
       this   implementation  provides  <STRONG>extended_slk_color</STRONG>  which  accepts  an
       integer value, e.g., 32-bits.


</PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
       These routines return <STRONG>ERR</STRONG> upon failure and <STRONG>OK</STRONG> (SVr4 specifies only  "an
       integer value other than <STRONG>ERR</STRONG>") upon successful completion.

       X/Open defines no error conditions.  In this implementation

          <STRONG>slk_attr</STRONG>
               returns the attribute used for the soft keys.

          <STRONG>slk_attroff</STRONG>,  <STRONG>slk_attron</STRONG>,  <STRONG>slk_clear</STRONG>,  <STRONG>slk_noutrefresh</STRONG>, <STRONG>slk_refresh</STRONG>,
          <STRONG>slk_touch</STRONG>
               return an error if  the  terminal  or  the  softkeys  were  not
               initialized.

          <STRONG>slk_attrset</STRONG>
               returns  an  error  if  the  terminal  or the softkeys were not
               initialized.

          <STRONG>slk_attr_set</STRONG>
               returns an error if the  terminal  or  the  softkeys  were  not
               initialized,   or   the   color   pair  is  outside  the  range
               0..COLOR_PAIRS-1.

          <STRONG>slk_color</STRONG>
               returns an error if the  terminal  or  the  softkeys  were  not
               initialized,   or   the   color   pair  is  outside  the  range
               0..COLOR_PAIRS-1.

          <STRONG>slk_init</STRONG>
               returns an error if the format parameter is outside  the  range
               0..3.

          <STRONG>slk_label</STRONG>
               returns <STRONG>NULL</STRONG> on error.

          <STRONG>slk_set</STRONG>
               returns  an  error  if  the  terminal  or the softkeys were not
               initialized, or the <EM>labnum</EM> parameter is outside  the  range  of
               label  counts,  or if the format parameter is outside the range
               0..2, or if memory for the labels cannot be allocated.


</PRE><H2><a name="h2-HISTORY">HISTORY</a></H2><PRE>
       SVr3 introduced these functions:
         slk_clear
         slk_init
         slk_label
         slk_noutrefresh
         slk_refresh
         slk_restore
         slk_set
         slk_touch

       SVr4 added these functions:
         slk_attroff
         slk_attron
         slk_attrset
         slk_start

       X/Open Curses added these:
         slk_attr_off
         slk_attr_on
         slk_attr_set
         slk_color
         slk_wset


</PRE><H2><a name="h2-EXTENSIONS">EXTENSIONS</a></H2><PRE>
       X/Open Curses documents the <EM>opts</EM> argument as reserved for  future  use,
       saying  that  it must be null.  This implementation uses that parameter
       in ABI 6 for the functions which have a color-pair parameter to support
       extended color pairs.

       For   functions  which modify the color, e.g., <STRONG>slk_attr_set</STRONG>, if <EM>opts</EM> is
       set it is treated as a pointer to <STRONG>int</STRONG>, and used  to   set   the   color
       pair instead of the <STRONG>short</STRONG> pair parameter.


</PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
       Most  applications  would  use  <STRONG>slk_noutrefresh</STRONG>  because  a <STRONG>wrefresh</STRONG> is
       likely to follow soon.


</PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
       The XSI Curses standard, Issue 4,  described  the  soft-key  functions,
       with some differences from SVr4 curses:

       <STRONG>o</STRONG>   It  added  functions like the SVr4 attribute-manipulation functions
           <STRONG>slk_attron</STRONG>,  <STRONG>slk_attroff</STRONG>,  <STRONG>slk_attrset</STRONG>,  but   which   use   <STRONG>attr_t</STRONG>
           parameters  (rather  than  <STRONG>chtype</STRONG>),  along  with  a  reserved  <EM>opts</EM>
           parameter.

           Two of these new functions (unlike  the  SVr4  functions)  have  no
           provision for color: <STRONG>slk_attr_on</STRONG> and <STRONG>slk_attr_off</STRONG>.

           The third function (<STRONG>slk_attr_set</STRONG>) has a color-pair parameter.

       <STRONG>o</STRONG>   It added <STRONG>const</STRONG> qualifiers to parameters (unnecessarily), and

       <STRONG>o</STRONG>   It added <STRONG>slk_color</STRONG>.

       Although  <STRONG>slk_start</STRONG>  is  declared in the curses header file, it was not
       documented by SVr4 other than its presence in a list of libtermlib.so.1
       symbols.  Reading the source code (i.e., Illumos):

       <STRONG>o</STRONG>   <STRONG>slk_start</STRONG> has two parameters:

           <STRONG>o</STRONG>   <EM>ng</EM> (number of groups) and

           <STRONG>o</STRONG>   <EM>gp</EM> (group pointer).

       <STRONG>o</STRONG>   Soft-key groups are an array of <EM>ng</EM> integers.

       <STRONG>o</STRONG>   In  SVr4, <STRONG>slk_init</STRONG> calls <STRONG>slk_start</STRONG> passing a null for <EM>gp</EM>.  For this
           case, <STRONG>slk_start</STRONG> uses the number of  groups  <EM>ng</EM>  (3  for  the  3-2-3
           layout, 2 for the 4-4 layout) which <STRONG>slk_init</STRONG> provided.

           If  <EM>ng</EM>  is  neither  2  or  3,  <STRONG>slk_start</STRONG>  checks  the terminfo <EM>fln</EM>
           (label_format) capability, interpreting that as  a  comma-separated
           list of numbers, e.g., "3,2,3" for the 3-2-3 layout.

           Finally, if there is no <EM>fln</EM> capability, <STRONG>slk_start</STRONG> returns ERR.

       <STRONG>o</STRONG>   If  <STRONG>slk_start</STRONG>  is given a non-null <EM>gp</EM>, it copies the <EM>ng</EM> elements of
           the group of soft-keys, up to 16.

           If there are more than 16 elements, <STRONG>slk_start</STRONG> returns an error.

       <STRONG>o</STRONG>   The format codes <STRONG>2</STRONG> and <STRONG>3</STRONG> for <STRONG>slk_init</STRONG>  were  added  by  ncurses  in
           1996.  PDCurses 2.4 added this feature in 2001.

       The function <STRONG>slk_attr</STRONG> was added by ncurses in 1996.

       X/Open  Curses  does  not  specify a limit for the number of colors and
       color pairs which a terminal can support.  However, in its use of <STRONG>short</STRONG>
       for  the  parameters,  it carries over SVr4's implementation detail for
       the compiled terminfo database, which uses signed 16-bit numbers.  This
       implementation  provides extended versions of those functions which use
       <STRONG>int</STRONG> parameters, allowing applications to use larger  color-  and  pair-
       numbers.


</PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
       <STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>,    <STRONG><A HREF="curs_attr.3x.html">curs_attr(3x)</A></STRONG>,    <STRONG><A HREF="curs_initscr.3x.html">curs_initscr(3x)</A></STRONG>,    <STRONG><A HREF="curs_refresh.3x.html">curs_refresh(3x)</A></STRONG>,
       <STRONG><A HREF="curs_variables.3x.html">curs_variables(3x)</A></STRONG>.



ncurses 6.4                       2023-09-16                      <STRONG><A HREF="curs_slk.3x.html">curs_slk(3x)</A></STRONG>
</PRE>
<div class="nav">
<ul>
<li><a href="#h2-NAME">NAME</a></li>
<li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
<li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
<ul>
<li><a href="#h3-Initialization">Initialization</a></li>
<li><a href="#h3-Labels">Labels</a></li>
<li><a href="#h3-Screen-updates">Screen updates</a></li>
<li><a href="#h3-Video-attributes">Video attributes</a></li>
<li><a href="#h3-Colors">Colors</a></li>
</ul>
</li>
<li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
<li><a href="#h2-HISTORY">HISTORY</a></li>
<li><a href="#h2-EXTENSIONS">EXTENSIONS</a></li>
<li><a href="#h2-NOTES">NOTES</a></li>
<li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
<li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>
</ul>
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